The present invention relates to pumps, and more generally to diaphragm pumps and diaphragms used in such pumps.
Diaphragm pumps that are driven by an electromagnetic device are well known to those skilled in the art. Diaphragm pumps are often not optimized for certain applications. For example, diaphragm pumps are often single acting (i.e., the working piston or diaphragm of the pump effectively pumps fluid only during a portion of its movement). As another example, diaphragm pumps are designed for pumping only one fluid at a time, despite the fact that it may often be desirable to pump two fluids simultaneously or closely in time. The rapid cycling of the drive mechanisms of such pumps can produce significant operation noise. Further, effectively sealing the electromagnetic or other drive mechanisms from the fluid being pumped is often essential to maintaining safe and effective pump operation, but can be difficult and costly and can adversely impact pump life.
It would be advantageous to provide an electromagnetically driven pump that addresses one or more of these concerns.
A number of pump embodiments according to the present invention are advantageously dual or double acting, thereby increasing pumping capacity. In addition, some of the pumps of the present invention reduce noise during operation. In some embodiments, the pumps of the present invention have self-priming capabilities. In certain embodiments, the pumps do not rely upon the fluid being pumped for lubrication, can be xe2x80x9crun dryxe2x80x9d for relatively long periods without incurring damage or without incurring significant damage. The diaphragms of the present invention are preferably configured to effectively seal the fluid being pumped from the electromagnetic drive assemblies, and in some embodiments can instead or in addition function to separate one fluid path through the pump from another. Many of the pumps and pump diaphragms according to the present invention are significantly more efficient, quiet, compact, have relatively long lives, and can be manufactured and assembled at relatively low cost.
In some preferred embodiments of the present invention, the pump includes a housing, a diaphragm, and an electromagnetic assembly. The pump housing has an inlet port, an outlet port, and a chamber in fluid communication with the inlet port and outlet port. As described in greater detail below, such pumps are capable of extended operation, can operate very effectively at high pressures, and have self-priming capabilities.
The diaphragm is preferably sealingly secured in the chamber and extends in at least one direction (and more preferably in both directions) to a sealed relationship with the housing. Some embodiments of the diaphragm have a central portion, a peripheral portion, and first and second projections. The central portion is adapted for movement relative to a housing of the pump to pump a fluid through the housing. The peripheral portion is preferably joined to the central portion and is adapted to be sealingly secured to the housing of the pump. The first and second projections (if employed) preferably extend generally axially outwardly from the central portion. Each of the first and second projections can include a sealing region that is adapted to be secured to the pump housing.
Although a number of different diaphragm shapes are possible, the diaphragm preferably has a central axis generally circumscribed by the peripheral portion. The first and second projections (if employed) preferably also circumscribe the central axis, and can be tubular structures or can have other shapes as desired.
Preferably, the diaphragm extends axially in either or both directions into apertures shaped to receive the axially-extending parts of the diaphragm. The diaphragm is preferably sealingly secured within first and second apertures located on respective axial sides of the diaphragm, and cooperates with the housing to define a fluid passageway between the inlet port and the outlet port. Specifically, some preferred diaphragm embodiments of the present invention include first and second seal portions configured to fluidly isolate the first and second apertures, respectively, from the fluid passageway between the inlet and outlet ports. The first and second seal portions extend axially away from each other and are preferably secured to the housing.
In some embodiments, the diaphragm includes an inner element or central portion that is more rigid than an outer portion of the diaphragm substantially surrounding the inner element. Force is preferably exerted by the plunger and a biasing assembly (described below) against the relatively rigid inner element of the diaphragm. For example, the relatively rigid inner element can be contacted and pushed or pulled by the plunger and the bias assembly, which lends sufficient strength and rigidity to the diaphragm such that the diaphragm can provide effective pumping action to pump fluid through the chamber. The relatively flexible outer portion of the diaphragm preferably allows the diaphragm to be sealingly secured to the housing while allowing oscillation of the diaphragm within the chamber to provide the desired pumping action. Preferably, the outer portion includes a radially extending peripheral zone that is sealingly secured to the housing. The diaphragm preferably has sufficient flexibility to deflect in response to movement of the plunger and the bias assembly without compromising the seals between the diaphragm and the housing.
Any of the diaphragms of the present invention can be structured such that when they are in a relaxed state, they are either substantially neutral or substantially biased in one direction. Thus, in some embodiments, the diaphragm is structured to be neutral when there are substantially no external forces applied thereto. In this respect, the diaphragm can be configured such that the central portion is spaced an equal distance from axially extending distal ends of the first and second projections of the diaphragm, although other relationships between such a central portion and distal ends is possible. In any case, this xe2x80x9cneutralxe2x80x9d type of diaphragm can be configured so that the central portion is substantially centrally located in the chamber when the pump is non-operative. In other embodiments, the present diaphragm is structured to be biased toward one end of the housing when there are substantially no external forces applied to the diaphragm. In other words, the diaphragm is configured to be biased toward one of the discharge position and the intake position of the pump. In this respect, the diaphragm can be configured such that the central portion is positioned closer to the distal end of the first projection relative to the distal end of the second projection. Such biasing of the diaphragm can provide enhanced pumping efficiency relative to a similar pump with a neutral diaphragm. For example, a diaphragm biased toward the intake position is effective in assisting a bias assembly (described in greater detail below) in returning the diaphragm to the intake position so that fluid flows efficiently into the fluid chamber. The diaphragm can be made of any suitable material effective to provide a diaphragm that functions as described herein. In some embodiments, the diaphragm is made of at least one polymeric material.
The diaphragm of the present invention is movable between a discharge position in which fluid in the fluid chamber is discharged to an cutlet port of the pump, and an intake position, in which fluid is passed from an inlet port of the pump into the fluid chamber.
In some embodiments of the present invention, the pump includes an inlet valve assembly positioned generally upstream of the chamber and adapted to control fluid flow between the inlet port and the fluid passageway. The pump can also include an outlet valve assembly positioned generally downstream of the chamber and adapted to control fluid flow between the fluid passageway and the outlet port. Also, some pumps according to the present invention have first and second inlet valve assemblies and first and second outlet valve assemblies. Each pair of inlet and outlet valve assemblies is preferably positioned in independent fluid passageways that are partially defined by opposing sides of the diaphragm. Thus, with the peripheral portion of the diaphragm sealingly secured to the housing, two isolated fluid passageways are provided in the chamber. One fluid passageway can be defined by one side of the diaphragm and at least one chamber wall, while the other fluid passageway can be defined by an opposite side of the diaphragm and at least one other chamber wall. In such embodiments, each fluid passageway can have different inlet and outlet valve assemblies.
Any suitable valve assembly may be employed as an inlet or outlet valve assembly in the present pumps. In some embodiments, each of the inlet and outlet valve assemblies comprises a valve chamber, a valve seat, a valve element (for example, in the shape of a partial sphere or ball) and a spring positioned to urge the valve element against the valve seat. Such biased valve assemblies are very effective in controlling positive flow through the pump while acting as check valves to substantially prevent unwanted back flow in the pump. Examples of valves that can be employed in the inlet and outlet valve assemblies of the present invention include flapper valves, leaf valves, snapper valves, ball valves, check valves (such as spring loaded check valves) and the like, many of which are of conventional and/or well known design and construction.
The electromagnetic assembly of the above-described embodiments can be secured to the housing and can include a plunger. Preferably, the plunger is configured to move to cause the diaphragm to move, thereby pumping fluid from the inlet port toward the outlet port. More specifically, the plunger is configured to move the diaphragm to at least one of the discharge position and the intake position.
In some embodiments, a bias assembly is positioned on an opposite side of the diaphragm and is adapted to urge the diaphragm to move toward the plunger. The bias assembly is preferably positioned to substantially oppose the electromagnetic assembly, to facilitate movement of the diaphragm toward at least one of the intake position and the discharge position, and preferably to contact both the housing and the diaphragm.
The bias assembly can take a number of different forms, and in some preferred embodiments includes a spring. The spring can cooperate with the electromagnetic assembly to impart reciprocal movement to the diaphragm. This combination of a bias assembly and an electromagnetic assembly can provide effective pumping action at relatively reduced cost compared to dual electromagnetic assembly pumps described elsewhere herein.
In some embodiments, a bias assembly can be located on the same side of the diaphragm as the plunger, and can have a biasing element (e.g., a spring) applying a biasing force to the plunger, urging the plunger toward the diaphragm. Such a bias assembly can be used in place of or in addition to the bias assembly described above to exert force upon the diaphragm. In some embodiments, this bias assembly can be connected to a rod configured to contact the diaphragm and to be moveable between a first position that corresponds to the discharge position of the diaphragm, and a second position that corresponds to the intake position of the diaphragm. The rod preferably is substantially freely moveable between the first position and the second position. One or more seals such as O-ring seals are preferably provided and are positioned about the rod. These seals are adapted to prevent the passage of fluid from the fluid chamber to other areas of the pump.
Either type of bias assembly described above can be located inside or outside of an aperture within which an extension of the diaphragm is received (as described above). The spring or other bias element used to exert the forces described above can also be (and preferably is) located outside of the chamber in which the diaphragm is located.
It may be desirable in some applications to adjust the amount of force exerted upon the plunger or upon the diaphragm by a bias assembly. In such cases, any of the bias assemblies described above can adjustable. Adjustment of the bias assemblies can be provided using any suitable structure. In some embodiments, a bias-adjusting member in the form of a nut threaded onto a threaded rod (such as the rod described above) connected to the plunger is provided. In such embodiments, the biasing member can be located between the nut and the end of the plunger. The threaded rod can be passed through the plunger (which is hollow in some embodiments) and into a center opening in the diaphragm. In this regard, the biasing force applied to the diaphragm and plunger can urge the diaphragm and plunger together, and can be adjusted by manipulation of the axial position of the nut on the threaded rod.
Some preferred embodiments of the present invention have electronic circuitry in electrical communication with an electromagnetic assembly driving the pump. This circuitry is configured to provide electrical energy to the electromagnetic assembly so as to cause the diaphragm to move, thereby moving the diaphragm between the intake position and the discharge position to pump fluid from the inlet port toward the outlet port. The electronic circuitry may be of conventional design effective to control the electromagnetic assembly so that the electromagnetic assembly and bias assembly cooperate to move the diaphragm in a substantially coordinated manner. Of course, other forms of electronic circuitry can instead be employed provided that such other forms function as described herein.
The electromagnetic assembly preferably includes a core that may, for example, be magnetic. Although a core is not required, a core is preferred for superior plunger control and power. The plunger of the electromagnetic assembly is preferably moveable relative to the core of the electromagnetic assembly. In some embodiments, such movement is controlled so that the plunger does not contact the core. Specifically, the electronic circuitry may be adapted to prevent contact between the plunger and the core. In these and other embodiments, the plunger can be sized and positioned so that the plunger is incapable of contacting the core. For example, the electromagnetic assembly can be sized so that the stroke or travel distance of the plunger is such that the plunger cannot contact the core at any point along the stroke of the plunger. Alternatively or in addition, the housing and/or the fluid in the fluid passageway can limit the movement of the diaphragm so that the stroke of the plunger is also limited, thereby limiting or preventing contact between the plunger and the core.
Preventing contact between the plunger and the core (when used) enhances the efficiency of the present pumps by avoiding the formation of a full or complete magnetic circuit between the plunger and the core. Were a full magnetic circuit to form, additional force or power could be required to separate the plunger and the core. In addition, by preventing the plunger from contacting the core, noise that would typically be associated with repeated contact between the plunger and the core is avoided. This reduces the overall noise level of the pump and can advantageously provide a more effective and efficient pump.
The plunger may be allowed to move solely in response to the electromagnetic forces being applied thereto. However, in one advantageous embodiment, the plunger is biased toward the diaphragm so as to be in substantially continuous contact with the diaphragm. Such substantially continuous contact prevents the development of a separation or a gap between the plunger and the diaphragm during operation. In some embodiments, the diaphragm is connected to the plunger by one or more fasteners, such as a screw or similar member inserted through the diaphragm (e.g., through the central portion of the diaphragm) and into the plunger, thereby maintaining the plunger in continuous contact with the diaphragm. Such biasing or substantially continuous plunger/diaphragm contact may be provided in any suitable way provided that the pumping action developed by the pump is not excessively adversely affected. Such biasing can significantly enhance the efficiency of the pump relative to a pump in which the plunger is not biased to remain in substantially continuous contact with the diaphragm. In some embodiments, such biasing forces the plunger against the diaphragm to creates a semi-rigid connection between the plunger, the diaphragm and the biasing assembly. The semi-rigid connection between the plunger, the diaphragm and the biasing assembly is preferred because the semi-rigid connection provides additional tolerance for minor imbalances of pump load as well as for variations in coordination between the electromagnetic assembly and the biasing assembly.
The various embodiments of pumps according to the present invention preferably employ an electromagnetic assembly for moving a plunger and diaphragm to pump fluid through the pump. However, it should be noted that other types of driving devices can instead be employed to move the diaphragm as described herein (whether through a plunger or otherwise). By way of example only, the electromagnetic assembly described above can be replaced by a hydraulic or pneumatic piston, a motor (driving the diaphragm through, for example, a cam connected to the motor and contacting the diaphragm or plunger), an electromagnet set connected to the diaphragm or plunger and to another surface adjacent to the diaphragm or plunger, and the like. Still other driving devices anti actuators are possible, each one of which can be controlled with the electronic circuitry described above to drive the diaphragm and to pump fluid through the pump.
Although the pumps according to the present invention are useful for pumping a single fluid, in some embodiments the pumps are adapted to pump two or more different fluids. As such, the present pumps can include a plurality of fluid passageways. Thus, although the same fluid can be used to pass through each of the different passageways alternatively, different fluids can be pumped through different passageways. In some embodiments for example, the pump includes two inlet ports and two outlet ports, while the diaphragm and the housing together define two mutually isolated fluid passageways. Different fluids can be pumped between each inlet port/outlet port pair and through each isolated fluid passageway.
The present pumps can be employed to pump fluids, such as liquids, at relatively low flow rates (although relatively high flow rate pumps according to the present invention are possible). For example, flow rates of about 0.5 liters/hr to about 100 liters/hr or more are common. Examples of useful applications include, without limitation, pumping floor cleaning chemicals for dispensing; plumping water to beverage dispensers; pumping comestible fluid; various automotive and vehicular applications, such as pumping a urea solution for a diesel emission control system; medical applications, and the like.
Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent.
These and other aspects and advantages of the present invention are apparent in the following detailed description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.